DE 10 2005 029 679 A1 describes a device and a method for joining pipe profiles with an inner pipe profile in an outer pipe profile through expansion by means of a rolling element, which is arranged in an expander head and, for the purpose of applying the rolling forces, is supported by means of a rotating support shaft. The rolling element moves epicyclically around the rotary axis of the support shaft, which runs eccentrically around the center axis of the pipe profiles. In order to shift the rolling element in the radial direction, the support shaft has a conical portion and can, in turn, be displaced in the axial direction. A support element that is embodied as a support roller, for example, is arranged on the expander head and supports the rolling forces against the inner surface of the inner pipe profile occurring on the rolling element. The expander head can be displaced along the pipe axis in order to create joining connections at various locations on the pipe profiles through expansion. This known device is also designed particularly for the joining of pipe profiles having smaller diameters.
In heavy-duty pipes, however, certain conditions are already present as a result of the large inside diameter of the pipe as well as metallurgic limitations. Namely, an outer pipe that it is generally (practically) impossible to expand elastically, which makes the necessary stable rolling-in of an inner cladding layer quite difficult. Heavy-duty pipes often not completely round, so that, due to the inhomogeneous pressing forces that occur in the presence of unroundness, it is difficult to achieve a uniformly stable connection of the cladding layer by a rotating support roller and an epicyclic rolling element driven by the same; that is, with a position-controlled pressing procedure.
Another coating device is described in WO 2004/103603 A1. This known coating device is designed to provide an outer pipe, which forms a carrier layer and is also referred to as a carrier pipe and has a cladding layer on the interior thereof. For this purpose, an inner pipe, also called a liner pipe or simply a liner, is pushed into the outer pipe and then expanded radially using an expander tool until it binds with the outer pipe, with the inner pipe being expanded plastically and the outer pipe being expanded in order to create a multilayer heavy-duty pipe. This process is repeated incrementally until the entire length of the heavy-duty pipe has been expanded. The expander tool is operated hydraulically (but dry), thus, excluding the possibility of the inner pipe coming into contact with the hydraulic fluid. The frictional mechanical bond between the two pipes is achieved by having the elastic resilience of the outer pipe be greater than the resilience of the inner pipe. This type of manufacture also influences the structure of the stable carrier pipe, and the combination of the materials of the inner pipe and of the carrier pipe must be selected such that the yield point of the inner pipe is lower than the yield point of the outer pipe, with corresponding limitations and drawbacks being associated with this.
During the manufacture of such multilayer heavy-duty pipes, the use of a coating device is also known which comprises a so-called hydroforming press (e.g., methods used by the Butting Group, a German-based pipe company). The inner pipe and the outer pipe are both slightly expanded by use of water pressure, with pressures being used that cause the outer pipe to flow, so that an outer casting is necessary in order protect the heavy-duty pipe from uncontrolled expansion and rupturing. Such a method has obvious drawbacks.
Another method for producing a multilayer heavy-duty pipe from an outer pipe and an inner pipe in the form of a largely frictionally connected cladding layer is described in DE 10 2013 103 811 B3. During manufacture, a carrier plate that already has a preformed initial bend is used, onto which a support plate is placed which is connected along its two longitudinal edges to the carrier plate, after which the interconnection to the multilayer heavy-duty pipe is formed and provided with a longitudinal weld seam. Such a method also has obvious drawbacks.
DE 10 2009 060 059 A1 also describes a method for producing a multilayer heavy-duty pipe. In this patent application, the wall of the heavy-duty pipe is formed from at least two metallic sheets that are integrally connected to one another by a solder introduced between the sheets. This type of connection requires special combinations of materials and a special production method that is adapted to them, which means that limitations exist from the outset.
Moreover, multilayer heavy-duty pipes are known which are plated with a cladding layer by metallurgic means as so-called “clad pipes” and thus, already formed in special production steps during the manufacture of the plate. When employing this procedure, however, narrow limits are set for the selection of material for many applications.